Balloon assembly for valvuloplasty catheter system

ABSTRACT

A catheter system ( 100 ) used for treating a treatment site ( 106 ) within or adjacent to the heart valve ( 108 ) includes an energy source ( 124 ), an energy guide ( 122 A), and a balloon assembly ( 104 ). The energy source ( 124 ) generates energy. The energy guide ( 122 A) is configured to receive energy from the energy source ( 124 ). The balloon assembly ( 104 ) is positionable substantially adjacent to the treatment site ( 106 ). The balloon assembly ( 104 ) includes an outer balloon ( 104 B) and an inner balloon ( 104 A) that is positioned substantially within the outer balloon ( 104 B). Each of the balloons ( 104 A,  104 B) has a balloon wall ( 130 ) that defines a balloon interior ( 146 ). Each of the balloons ( 104 A,  104 B) is configured to retain a balloon fluid ( 132 ) within the balloon interior ( 146 ). The balloon wall ( 130 ) of the inner balloon ( 104 A) is positioned spaced apart from the balloon wall ( 130 ) of the outer balloon ( 104 B) to define an interstitial space ( 146 A) therebetween. A portion of the energy guide ( 122 A) that receives the energy from the energy source ( 124 ) is positioned within the interstitial space ( 146 A) between the balloons ( 104 A,  104 B) so that a plasma-induced bubble ( 134 ) is formed in the balloon fluid ( 132 ) within the interstitial space ( 146 A).

RELATED APPLICATION

This application claims priority from U.S. Provisional Application Ser. No. 63/136,474, filed on Jan. 12, 2021. To the extent permitted, the contents of U.S. Provisional Application Ser. No. 63/136,474 are incorporated in their entirety herein by reference.

BACKGROUND

Vascular lesions, such as calcium deposits, within and adjacent to heart valves in the body can be associated with an increased risk for major adverse events, such as myocardial infarction, embolism, deep vein thrombosis, stroke, and the like. Severe vascular lesions, such as severely calcified vascular lesions, can be difficult to treat and achieve patency for a physician in a clinical setting.

The aortic valve is a valve of the human heart between the left ventricle and the aorta. The aortic valve functions as a one-way valve and typically includes three leaflets which open and close in unison when the valve is functioning properly. During normal operation, when the left ventricle contracts (during ventricular systole), pressure rises in the left ventricle. When the pressure in the left ventricle rises above the pressure in the aorta, the aortic valve opens, allowing blood to exit the left ventricle into the aorta. When ventricular systole ends, pressure in the left ventricle rapidly drops. When the pressure in the left ventricle decreases, the momentum of the vortex at the outlet of the valve forces the aortic valve to close. Dysfunction or improper operation of the aortic valve can result in left ventricular hypertrophy (enlargement and thickening of the walls of the left ventricle) and/or aortic valve regurgitation, which is the backflow of blood from the aorta into the left ventricle during diastole. Such issues can lead to heart failure if left uncorrected.

A calcium deposit on the aortic valve, known as aortic valve stenosis, can form adjacent to a valve wall of the aortic valve and/or on or between the leaflets of the aortic valve. Aortic valve stenosis can prevent the leaflets from opening and closing completely, which can, in turn, result in the undesired aortic valve regurgitation. Over time, such calcium deposits can cause the leaflets to become less mobile and ultimately prevent the heart from supplying enough blood to the rest of the body.

Certain methods are currently available which attempt to address aortic valve stenosis, but such methods have not been altogether satisfactory. Certain such methods include using a standard balloon valvuloplasty catheter, and artificial aortic valve replacement, which can be used to restore functionality of the aortic valve. During aortic valvuloplasty, a balloon is expanded at high pressure in the inside of the aortic valve to break apart calcification on the valve leaflets cusps and between the commissures of the valve leaflets. Usually, this procedure is done prior to placing a replacement aortic valve. Certain anatomical factors such as heavily calcified valves can prevent the valvuloplasty from being effective enough for valve placement, causing performance and safety concerns for the replacement valve. In order for the replacement valve to function correctly it must be precisely positioned over the native valve. Stated in another manner, aortic valvuloplasty often does not have enough strength to sufficiently disrupt the calcium deposit between the leaflets or at the base of the leaflets, which can subsequently adversely impact the effectiveness of any aortic valve replacement procedure. Aortic valve replacement can also be highly invasive and extremely expensive. In still another such method, a valvular stent can be placed between the leaflets to bypass the leaflets. This procedure is relatively costly, and results have found that the pressure gradient does not appreciably improve.

Thus, there is an ongoing desire to develop improved methodologies for valvuloplasty in order to more effectively and efficiently break up calcium deposits adjacent to the valve wall of the aortic valve and/or on or between the leaflets of the aortic valve. Additionally, it is desired that such improved methodologies work effectively to address not only aortic valve stenosis related to the aortic valve, but also calcification on other heart valves, such as mitral valve stenosis within the mitral valve, valvular stenosis within the tricuspid valve, and pulmonary valve stenosis within the pulmonary valve.

SUMMARY

The present invention is directed toward a catheter system used for treating a treatment site within or adjacent to the heart valve within a body of a patient. In various embodiments, the catheter system includes an energy source, an energy guide, and a balloon assembly. The energy source generates energy. The energy guide is configured to receive energy from the energy source. The balloon assembly is positionable substantially adjacent to the treatment site. The balloon assembly includes an outer balloon and an inner balloon that is positioned substantially within the outer balloon. Each of the balloons has a balloon wall that defines a balloon interior. Each of the balloons is configured to retain a balloon fluid within the balloon interior. The balloon wall of the inner balloon is positioned spaced apart from the balloon wall of the outer balloon to define an interstitial space therebetween. A portion of the energy guide that receives the energy from the energy source is positioned within the interstitial space between the balloons so that a plasma-induced bubble (also sometimes referred to herein as “plasma”) is formed in the balloon fluid within the interstitial space.

In some embodiments, the energy guide includes a guide distal end that is positioned within the interstitial space between the balloons so that the plasma-induced bubble is formed in the balloon fluid within the interstitial space.

In certain embodiments, each of the balloons is selectively inflatable with the balloon fluid to expand to an inflated state.

In various embodiments, when the balloons are in the inflated state the balloon wall of the inner balloon is spaced apart from the balloon wall of the outer balloon to define the interstitial space therebetween.

In some embodiments, when the balloons are in the inflated state, the outer balloon is configured to be positioned substantially adjacent to the treatment site.

In certain embodiments, when the balloons are in the inflated state, the inner balloon has an inner balloon diameter, and the outer balloon has an outer balloon diameter that is greater than the inner balloon diameter of the inner balloon.

In various embodiments, when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 5% greater than the inner balloon diameter of the inner balloon.

In some embodiments, when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 10% greater than the inner balloon diameter of the inner balloon.

In certain embodiments, when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 20% greater than the inner balloon diameter of the inner balloon.

In some embodiments, when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 30% greater than the inner balloon diameter of the inner balloon.

In certain embodiments, when the balloons are in the inflated state, the inner balloon is inflated to a greater inflation pressure than the outer balloon.

In some embodiments, when the balloons are in the inflated state, the inner balloon has a first balloon shape and the outer balloon has a second balloon shape that is different from the first balloon shape.

In certain embodiments, the inner balloon is made from a first material, and the outer balloon is made from a second material that is different from the first material.

In various embodiments, the first material can have a first compliance, and the second material can have a second compliance that is greater than the first compliance so that the outer balloon expands at a faster rate than the inner balloon when the balloons are expanded to an inflated state.

In some embodiments, the first material is non-compliant, and the second material is semi-compliant.

In certain embodiments, the first material is non-compliant, and the second material is compliant.

In various embodiments, the first material is semi-compliant, and the second material is compliant.

In some embodiments, the energy guide is positioned substantially directly adjacent to an outer surface of the inner balloon.

In certain embodiments, the energy guide is adhered to the outer surface of the inner balloon.

In various embodiments, the energy guide is positioned spaced apart from the outer surface of the inner balloon.

In some embodiments, the catheter system further includes a guide support structure that is mounted on the outer surface of the inner balloon, and the energy guide is positioned on the guide support structure so that the energy guide is positioned spaced apart from the outer surface of the inner balloon.

In certain implementations, the heart valve includes a valve wall; and the balloon assembly is positioned adjacent to the valve wall.

In various implementations, the heart valve includes a plurality of leaflets; and the balloon assembly is positioned adjacent to at least one of the plurality of leaflets.

In some embodiments, the catheter system further includes a plasma generator that is positioned near a guide distal end of the energy guide, the plasma generator being configured to generate the plasma-induced bubble in the balloon fluid within the interstitial space between the balloons.

In certain embodiments, the guide distal end of the energy guide is positioned within the interstitial space between the balloons approximately at a midpoint of the heart valve.

In some embodiments, the plasma-induced bubble formation imparts pressure waves upon the balloon wall of the outer balloon adjacent to the treatment site.

In certain embodiments, the energy source generates pulses of energy that are guided along the energy guide into the interstitial space between the balloons to generate the plasma-induced bubble formation in the balloon fluid within the interstitial space between the balloons.

In various embodiments, the energy source is a laser source that provides pulses of laser energy.

In some embodiments, the energy guide can include an optical fiber.

In certain embodiments, the energy source is a high voltage energy source that provides pulses of high voltage.

In some embodiments, the energy guide can include an electrode pair including spaced apart electrodes that extend into the interstitial space between the balloons.

In various embodiments, pulses of high voltage from the energy source are applied to the electrodes and form an electrical arc across the electrodes.

In certain embodiments, the catheter system further includes a catheter shaft, and a balloon proximal end of at least one of the balloons can be coupled to the catheter shaft.

In some embodiments, the catheter system further includes (i) a guide shaft that is positioned at least partially within the catheter shaft, the guide shaft defining a guidewire lumen, and (ii) a guidewire that is positioned to extend through the guidewire lumen, the guidewire being configured to guide movement of the balloon assembly so that the balloon assembly is positioned substantially adjacent to the treatment site.

In various embodiments, the catheter system further includes a plurality of energy guides that are configured to receive energy from the energy source, and a portion of each of the plurality of energy guides that receive the energy from the energy source can be positioned within the interstitial space between the balloons so that a plasma-induced bubble is formed in the balloon fluid within the interstitial space.

The present invention is also directed toward a method for treating a treatment site within or adjacent to a heart valve within a body of a patient, the method including the steps of (i) generating energy with an energy source; (ii) receiving energy from the energy source with an energy guide; (iii) positioning a balloon assembly substantially adjacent to the treatment site, the balloon assembly including an outer balloon and an inner balloon that is positioned substantially within the outer balloon, each of the balloons having a balloon wall that defines a balloon interior, each of the balloons being configured to retain a balloon fluid within the balloon interior, the balloon wall of the inner balloon being positioned spaced apart from the balloon wall of the outer balloon to define an interstitial space therebetween; and (iv) positioning a portion of the energy guide that receives the energy from the energy source within the interstitial space between the balloons so that a plasma-induced bubble is formed in the balloon fluid within the interstitial space.

The present invention is also directed toward a catheter system for treating a treatment site within or adjacent to a heart valve within a body of a patient, including an energy source, an energy guide, and a balloon assembly. In various embodiments, the energy source generates energy. The energy guide is configured to receive energy from the energy source. The balloon assembly is positionable adjacent to the treatment site. The balloon assembly can include an outer balloon and an inner balloon that is positioned substantially within the outer balloon. The inner balloon can be made from a first material having a first compliance, and the outer balloon can be made from a second material that is different from the first material. In certain embodiments, the second material can have a second compliance that is greater than the first compliance. Each of the balloons can have a balloon wall that defines a balloon interior. Each of the balloons can be configured to retain a balloon fluid within the balloon interior. The balloon wall of the inner balloon can be positioned spaced apart from the balloon wall of the outer balloon to define an interstitial space therebetween. Each of the balloons can be inflatable with the balloon fluid to expand to an inflated state. In various embodiments, when the balloons are in the inflated state, (i) the inner balloon has an inner balloon diameter, (ii) the outer balloon has an outer balloon diameter that is at least approximately 5% greater than the inner balloon diameter, and/or (iii) the inner balloon is inflated to a greater inflation pressure than the outer balloon. In at least some embodiments, a portion of the energy guide can be positioned within the interstitial space between the balloons to generate a plasma-induced bubble in the balloon fluid within the interstitial space upon the energy guide receiving energy from the energy source.

This summary is an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details are found in the detailed description and appended claims. Other aspects will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which is not to be taken in a limiting sense. The scope herein is defined by the appended claims and their legal equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

FIG. 1 is a schematic cross-sectional view of an embodiment of a catheter system in accordance with various embodiments herein, the catheter system including a valvular lithoplasty balloon assembly having features of the present invention;

FIG. 2A is a simplified side view of a portion of a heart valve and a portion of an embodiment of the catheter system including an embodiment of the valvular lithoplasty balloon assembly;

FIG. 2B is a simplified cutaway view of the catheter system including the valvular lithoplasty balloon assembly taken on line 2B-2B in FIG. 2A;

FIG. 3 is a simplified cutaway view of a portion of another embodiment of the catheter system including another embodiment of the valvular lithoplasty balloon assembly; and

FIG. 4 is a simplified side view of a portion of a fluid flow system usable within the catheter system.

While embodiments of the present invention are susceptible to various modifications and alternative forms, specifics thereof have been shown by way of example and drawings, and are described in detail herein. It is understood, however, that the scope herein is not limited to the particular embodiments described. On the contrary, the intention is to cover modifications, equivalents, and alternatives falling within the spirit and scope herein.

DESCRIPTION

Treatment of vascular lesions (also sometimes referred to herein as “treatment sites”) can reduce major adverse events or death in affected subjects. As referred to herein, a major adverse event is one that can occur anywhere within the body due to the presence of a vascular lesion. Major adverse events can include, but are not limited to, major adverse cardiac events, major adverse events in the peripheral or central vasculature, major adverse events in the brain, major adverse events in the musculature, or major adverse events in any of the internal organs.

As used herein, the terms “treatment site”, “intravascular lesion” and “vascular lesion” are used interchangeably unless otherwise noted. As such, the intravascular lesions and/or the vascular lesions are sometimes referred to herein simply as “lesions”.

Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Additionally, other methods of delivering energy to the lesion can be utilized, including, but not limited to electric current induced plasma generation. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings. The same or similar nomenclature and/or reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts.

In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It is appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with application-related and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it is recognized that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

The catheter systems disclosed herein can include many different forms. Referring now to FIG. 1 , a schematic cross-sectional view is shown of a catheter system 100 in accordance with various embodiments. The catheter system 100 is suitable for imparting pressure waves to induce fractures in one or more treatment sites within or adjacent leaflets within the aortic valve or other appropriate heart valve. In the embodiment illustrated in FIG. 1 , the catheter system 100 can include one or more of a catheter 102, an energy guide bundle 122 including one or more energy guides 122A, a source manifold 136, a fluid pump 138, a system console 123 including one or more of an energy source 124, a power source 125, a system controller 126, and a graphic user interface 127 (a “GUI”), and a handle assembly 128. Additionally, as described herein, the catheter 102 includes a valvular lithoplasty balloon assembly 104 (also sometimes referred to herein simply as a “balloon assembly”), including an inner balloon 104A and an outer balloon 104B, that is configured to be selectively positioned adjacent to a valve wall 108A (including annulus and commissures) and/or on or between adjacent leaflets 108B within a heart valve 108, e.g., the aortic valve, at a treatment site 106. Alternatively, the catheter system 100 can have more components or fewer components than those specifically illustrated and described in relation to FIG. 1 .

The catheter 102 is configured to move to the treatment site 106 within or adjacent to the heart valve 108 within a body 107 of a patient 109. The treatment site 106 can include one or more vascular lesions 106A such as calcified vascular lesions, for example. Additionally, or in the alternative, the treatment site 106 can include vascular lesions 106A such as fibrous vascular lesions.

It is appreciated that the illustration of the heart valve 108 in FIG. 1 , including the valve wall 108A and the leaflets 108B, is merely a simplified representation of the heart valve 108, and is not intended to represent the actual size and shape of the heart valve 108 and the components thereof. It is also appreciated that FIG. 1 further illustrates certain portions of a heart wall of a heart of the patient 109 that extend in either direction away from the heart valve 108. It is further appreciated that the heart wall of the heart is illustrated as a straight tube in FIG. 1 for purposes of simplicity, and the actual shape of the heart wall is reality is much more complex than what is actually shown in FIG. 1 .

The catheter 102 can include a catheter shaft 110, a guide shaft 118, the valvular lithoplasty balloon assembly 104, and a guidewire 112.

The catheter shaft 110 can extend from a proximal portion 114 of the catheter system 100 to a distal portion 116 of the catheter system 100. The catheter shaft 110 can include a longitudinal axis 144. The guide shaft 118 can be positioned, at least in part, within the catheter shaft 110. The guide shaft 118 can define a guidewire lumen which is configured to move over the guidewire 112 and/or through which the guidewire 112 extends. The catheter shaft 110 can further include one or more inflation lumens (not shown) and/or various other lumens for various other purposes. For example, in one embodiment, the catheter shaft 110 includes a separate inflation lumen that is configured to provide a balloon fluid 132 for each of the inner balloon 104A and the outer balloon 104B of the balloon assembly 104. In some embodiments, the catheter 102 can have a distal end opening 120 and can accommodate and be tracked over the guidewire 112 as the catheter 102 is moved and positioned at or near the treatment site 106.

The balloon assembly 104 can be coupled to the catheter shaft 110. In various embodiments, the balloon assembly 104 includes the inner balloon 104A and the outer balloon 104B, which is positioned to substantially, if not entirely, encircle the inner balloon 104A. Stated in another manner, the balloon assembly 104 includes the outer balloon 104B, and the inner balloon 104A that is positioned at least substantially, if not entirely, within the outer balloon 104B. During use of the catheter system 100, the outer balloon 104B can be positioned adjacent to the valve wall 108A and/or on or between adjacent leaflets 108B within the heart valve 108 at the treatment site 106.

Each balloon 104A, 104B of the balloon assembly 104 can include a balloon proximal end 104P and a balloon distal end 104D. In some embodiments, the balloon proximal end 104P of at least one of the balloons 104A, 104B can be coupled to the catheter shaft 110. Additionally, in certain embodiments, the balloon distal end 104D of at least one of the balloons 104A, 104B can be coupled to the guide shaft 118. For example, in some embodiments, the balloon proximal end 104P of the inner balloon 104A is coupled to and/or secured to the catheter shaft 110 and the balloon distal end 104D of the inner balloon 104A is coupled to and/or secured to the guide shaft 118; and the balloon proximal end 104P of the outer balloon 104B is coupled to and/or secured to the balloon proximal end 104P of the inner balloon 104A and the balloon distal end 104D of the outer balloon 104A is coupled to and/or secured to the balloon distal end 104D of the inner balloon 104A. Alternatively, in other embodiments, the balloon proximal end 104P of each of the inner balloon 104A and the outer balloon 104B is coupled to and/or secured to the catheter shaft 110; and the balloon distal end 104D of each of the inner balloon 104A and the outer balloon 104B is coupled to and/or secured to the guide shaft 118.

It is appreciated that the inner balloon 104A can be coupled to and/or secured to the catheter shaft 110 and the guide shaft 118 in any suitable manner. For example, in one non-exclusive embodiment, the balloon proximal end 104P of the inner balloon 104A can be heat-bonded to the catheter shaft 110, and the balloon distal end 104D of the inner balloon 104A can be heat-bonded to the guide shaft 118. Similarly, the outer balloon 104B can be coupled to and/or secured to the catheter shaft 110, the guide shaft 118 and/or the inner balloon 104A in any suitable manner. For example, in one non-exclusive embodiment, the balloon proximal end 104P of the outer balloon 104B can be heat-bonded to the catheter shaft 110, and the balloon distal end 104D of the outer balloon 104B can be heat-bonded to the guide shaft 118. Alternatively, in another embodiment, the balloon proximal end 104P of the outer balloon 104B can be heat-bonded to the balloon proximal end 104P of the inner balloon 104A, and/or the balloon distal end 104D of the outer balloon 104B can be heat-bonded to the balloon distal end 104D of the inner balloon 104A. Still alternatively, the inner balloon 104A can be coupled to and/or secured to the catheter shaft 110 and the guide shaft 118 in another suitable manner, and/or the outer balloon 104B can be coupled to and/or secured to the catheter shaft 110, the guide shaft 118 and/or the inner balloon 104A in another suitable manner, such as with adhesives.

Each balloon 104A, 104B includes a balloon wall 130 that defines a balloon interior 146. Each balloon 104A, 104B can be selectively inflated with the balloon fluid 132 to expand from a deflated state suitable for advancing the catheter 102 through a patient's vasculature, to an inflated state (as shown in FIG. 1 ) suitable for anchoring the catheter 102 in position relative to the treatment site 106. In particular, when the balloons 104A, 104B are in the inflated state, the balloon wall 130 of the outer balloon 104B is configured to be positioned substantially adjacent to the treatment site 106.

Additionally, as shown in FIG. 1 , when the balloons 104A, 104B are in the inflated state, at least a portion of the balloon wall 130 of the outer balloon 104B is spaced apart from the balloon wall 130 of the inner balloon 104A so as to define an interstitial space 146A therebetween. It is appreciated that the interstitial space 146A between the inner balloon 104A and the outer balloon 104B when the balloons 104A, 104B are in the inflated state can be created in any suitable manner. For example, in certain non-exclusive embodiments, the interstitial space 146A between the inner balloon 104A and the outer balloon 104B can be created by one or more of (i) forming the inner balloon 104A and the outer balloon 104B from different materials from one another, (ii) forming the inner balloon 104A and the outer balloon 104B to have different diameters from one another when inflated, and (iii) forming the inner balloon 104A and the outer balloon 104B to have different shapes from one another when inflated.

The balloons 104A, 104B can be formed from any suitable materials. The balloons 104A, 104B suitable for use in the balloon assembly 104 within the catheter system 100 include those that can be passed through the vasculature of a patient when in the deflated state. In various embodiments, the inner balloon 104A and the outer balloon 104B can be formed from different materials, such as having the outer balloon 104B made from a material that is more compliant than the material used for the inner balloon 104A so that when the two balloons 104A, 104B are inflated the outer balloon 104B can expand at a different, faster rate than the inner balloon 104A and therefore create a larger interstitial space 146A between the balloons 104A, 104B. More specifically, in certain embodiments, the outer balloon 104B has an outer balloon compliance over a working range as the outer balloon 104B is expanded from the deflated state to the inflated state, and the inner balloon 104A has an inner balloon compliance over a working range as the inner balloon 104A is expanded from the deflated state to the inflated state. In some such embodiments, the outer balloon compliance of the outer balloon 104B can be at least approximately 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 25%, 30%, 35%, 40%, 45% or 50% greater that the inner balloon compliance of the inner balloon 104A. Alternatively, the difference between the outer balloon compliance of the outer balloon 104B and the inner balloon compliance of the inner balloon 104A can be different than the values noted above.

In some embodiments, the balloons 104A, 104B are made from silicone. In other embodiments, the balloons 104A, 104B can be made from materials such as polydimethylsiloxane (PDMS), polyurethane, polymers such as PEBAX™ material, nylon, polyethylene terephthalate (PET), or any other suitable material. Additionally, in certain embodiments, the balloons 104A, 104B can be impermeable, such that no apertures are intentionally formed into and/or through the balloon wall 130 to allow the balloon fluid 132 and/or any suitable therapeutic agent to pass therethrough.

In certain embodiments, the outer balloon 104B can be formed from compliant materials such as urethanes, lower durometer PEBAX™, and nylons, or semi-compliant materials such as PEBAX™, and nylon blends with urethanes and silicone; and the inner balloon 104A can be formed from semi-compliant materials such as PEBAX™, and nylon blends with urethanes and silicone, or non-compliant materials such as PET. More specifically, in one non-exclusive such embodiment, the outer balloon 104B can be formed from a compliant material and the inner balloon 104A can be formed from a semi-compliant material. In another non-exclusive such embodiment, the outer balloon 104B can be formed from a compliant material and the inner balloon 104A can be formed from a non-compliant material. In still another non-exclusive such embodiment, the outer balloon 104B can be formed from a semi-compliant material and the inner balloon 104A can be formed from a non-compliant material. As noted, the different compliances between the materials for the outer balloon 104B and the inner balloon 104A are configured such that the balloons 104A, 104B expand at different rates to help create the interstitial space 146A between the balloons 104A, 104B when the balloons 104A, 104B are in the inflated state.

As utilized herein, a non-compliant or semi-compliant balloon is defined as one that inflates to a predetermined shape, and changes to this shape are relatively insensitive to the internal inflation pressure. For example, in some non-exclusive applications, a non-compliant balloon is a balloon with less than approximately 6% compliance over a working range, and a semi-compliant balloon is a balloon with between approximately 6% to 12% compliance over the working range. Additionally, in such applications, a compliant balloon is a balloon with greater than 12% compliance over the working range.

The balloons 104A, 104B can have any suitable diameter (in the inflated state). In various embodiments, the balloons 104A, 104B can have a diameter (in the inflated state) ranging from less than one millimeter (mm) up to 30 mm. In some embodiments, the balloons 104A, 104B can have a diameter (in the inflated state) ranging from at least 1.5 mm up to 14 mm. In some embodiments, the balloons 104A, 104B can have a diameter (in the inflated state) ranging from at least two mm up to five mm.

In various embodiments, the outer balloon 104B and the inner balloon 104A are configured to have different diameters from one another when the balloons 104A, 104B are in the inflated state. In certain non-exclusive alternative embodiments, the inner balloon 104A can have an inner balloon diameter when in the inflated state, and the outer balloon 104B can have an outer balloon diameter when in the inflated state that is at least approximately 1%, 2%, 3%, 5%, 7%, 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47% or 50% greater than the inner balloon diameter of the inner balloon 104A. Alternatively, the difference between the outer balloon diameter of the outer balloon 104B and the inner balloon diameter of the inner balloon 104A can be different than the values noted above. As noted, the difference between the outer balloon diameter and the inner balloon diameter, with the outer balloon diameter being greater than the inner balloon diameter, is configured to help create the interstitial space 146A between the balloons 104A, 104B when the balloons 104A, 104B are in the inflated state.

In some embodiments, the balloons 104A, 104B can have a length ranging from at least three mm to 300 mm. More particularly, in some embodiments, the balloons 104A, 104B can have a length ranging from at least eight mm to 200 mm. It is appreciated that balloons 104A, 104B having a relatively longer length can be positioned adjacent to larger treatment sites 106, and, thus, may be usable for imparting pressure waves onto and inducing fractures in larger vascular lesions 106A or multiple vascular lesions 106A at precise locations within the treatment site 106. It is further appreciated that longer balloons 104A, 104B can also be positioned adjacent to multiple treatment sites 106 at any one given time.

The balloons 104A, 104B can be inflated to inflation pressures of between approximately one atmosphere (atm) and 70 atm. In some embodiments, the balloons 104A, 104B can be inflated to inflation pressures of from at least 20 atm to 60 atm. In other embodiments, the balloons 104A, 104B can be inflated to inflation pressures of from at least six atm to 20 atm. In still other embodiments, the balloons 104A, 104B can be inflated to inflation pressures of from at least three atm to 20 atm. In yet other embodiments, the balloons 104A, 104B can be inflated to inflation pressures of from at least two atm to ten atm.

In certain embodiments, the inner balloon 104A and the outer balloon 104B can be inflated to different inflation pressures. In such embodiments, the inner balloon 104A can be pressurized at a higher inflation pressure than the outer balloon 104B to improve the energy transfer by better directing the energy into the vascular lesions 106A at the treatment site 106. More specifically, the improved energy transfer is achieved by keeping the balloon wall 130 of the inner balloon 104A immovable at high pressure so that the energy is not absorbed by movement of the balloon wall 130 of the inner balloon 104A, but rather is directed in a generally outward direction to the balloon wall 130 of the outer balloon 104B positioned at the treatment site 106. In certain non-exclusive embodiments, the inner balloon 104A can be inflated to an inflation pressure that is between approximately 0.1 atm and 8 atmospheres greater than the inflation pressure for the outer balloon 104B. Alternatively, the difference in inflation pressure in the inner balloon 104A and the outer balloon 104B can be different than the values noted above.

The balloons 104A, 104B can have various shapes, including, but not to be limited to, a conical shape, a square shape, a rectangular shape, a spherical shape, a conical/square shape, a conical/spherical shape, an extended spherical shape, an oval shape, a tapered shape, a bone shape, an hourglass shape, a stepped diameter shape, an offset or asymmetrical shape, or a conical offset shape. In some embodiments, the balloons 104A, 104B can include a drug eluting coating, or a drug eluting stent structure. The drug eluting coating or drug eluting stent can include one or more therapeutic agents including anti-inflammatory agents, anti-neoplastic agents, anti-angiogenic agents, and the like. In other embodiments, the balloons 104A, 104B can include any suitable type of stent structure. Additionally or in the alternative, in various applications, use of a stent is inappropriate and the valvuloplasty procedure can be followed by the positioning of an artificial replacement valve into the valve area.

In various embodiments, the shape of the inner balloon 104A can be different than the shape of the outer balloon 104B to help create the interstitial space 146A between the balloons 104A, 104B when the balloons 104A, 104B are in the inflated state. More particularly, in such embodiments, the inner balloon 104A can have a first shape and the outer balloon 104B can have a second shape that is different than the first shape to help create the interstitial space 146A and to more effectively optimize energy delivery.

The balloon fluid 132 can be a liquid or a gas. Some examples of the balloon fluid 132 suitable for use can include, but are not limited to one or more of water, saline, contrast medium, fluorocarbons, perfluorocarbons, gases, such as carbon dioxide, or any other suitable balloon fluid 132. In some embodiments, the balloon fluid 132 can be used as a base inflation fluid. In some embodiments, the balloon fluid 132 can include a mixture of saline to contrast medium in a volume ratio of approximately 50:50. In other embodiments, the balloon fluid 132 can include a mixture of saline to contrast medium in a volume ratio of approximately 25:75. In still other embodiments, the balloon fluid 132 can include a mixture of saline to contrast medium in a volume ratio of approximately 75:25. However, it is understood that any suitable ratio of saline to contrast medium can be used. The balloon fluid 132 can be tailored on the basis of composition, viscosity, and the like so that the rate of travel of the pressure waves are appropriately manipulated. In certain embodiments, the balloon fluids 132 suitable for use are biocompatible. A volume of balloon fluid 132 can be tailored by the chosen energy source 124 and the type of balloon fluid 132 used.

In some embodiments, the contrast agents used in the contrast media can include, but are not to be limited to, iodine-based contrast agents, such as ionic or non-ionic iodine-based contrast agents. Some non-limiting examples of ionic iodine-based contrast agents include diatrizoate, metrizoate, iothalamate, and ioxaglate. Some non-limiting examples of non-ionic iodine-based contrast agents include iopamidol, iohexol, ioxilan, iopromide, iodixanol, and ioversol. In other embodiments, non-iodine based contrast agents can be used. Suitable non-iodine containing contrast agents can include gadolinium (III)-based contrast agents. Suitable fluorocarbon and perfluorocarbon agents can include, but are not to be limited to, agents such as the perfluorocarbon dodecafluoropentane (DDFP, C5F12).

The balloon fluids 132 can include those that include absorptive agents that can selectively absorb light in the ultraviolet region (e.g., at least ten nanometers (nm) to 400 nm), the visible region (e.g., at least 400 nm to 780 nm), or the near-infrared region (e.g., at least 780 nm to 2.5 μm) of the electromagnetic spectrum. Suitable absorptive agents can include those with absorption maxima along the spectrum from at least ten nm to 2.5 μm. Alternatively, the balloon fluids 132 can include those that include absorptive agents that can selectively absorb light in the mid-infrared region (e.g., at least 2.5 μm to 15 μm), or the far-infrared region (e.g., at least 15 μm to one mm) of the electromagnetic spectrum. In various embodiments, the absorptive agent can be those that have an absorption maximum matched with the emission maximum of the laser used in the catheter system 100. By way of non-limiting examples, various lasers usable in the catheter system 100 can include neodymium:yttrium-aluminum-garnet (Nd:YAG−emission maximum=1064 nm) lasers, holmium:YAG (Ho:YAG−emission maximum=2.1 μm) lasers, or erbium:YAG (Er:YAG−emission maximum=2.94 μm) lasers. In some embodiments, the absorptive agents can be water soluble. In other embodiments, the absorptive agents are not water soluble. In some embodiments, the absorptive agents used in the balloon fluids 132 can be tailored to match the peak emission of the energy source 124. Various energy sources 124 having emission wavelengths of at least ten nanometers to one millimeter are discussed elsewhere herein.

The catheter shaft 110 of the catheter 102 can be coupled to the one or more energy guides 122A of the energy guide bundle 122 that are in optical communication with the energy source 124. Each energy guide 122A can be disposed along the catheter shaft 110 and within the interstitial space 146A between the inner balloon 104A and the outer balloon 104B. In some embodiments, each energy guide 122A can be adhered and/or attached to an outer surface 104S of the inner balloon 104A. Alternatively, in other embodiments, one or more of the energy guides 122A can be fixed onto a separate support structure (not shown in FIG. 1 ) such as a nitinol scaffold. In some embodiments, each energy guide 122A can be an optical fiber and the energy source 124 can be a laser. The energy source 124 can be in optical communication with the energy guides 122A at the proximal portion 114 of the catheter system 100.

In some embodiments, the catheter shaft 110 can be coupled to multiple energy guides 122A such as a first energy guide, a second energy guide, a third energy guide, a fourth energy guide, etc., which can be disposed at any suitable positions about the guide shaft 118 and/or the catheter shaft 110. For example, in certain non-exclusive embodiments, two energy guides 122A can be spaced apart by approximately 180 degrees about the circumference of the guide shaft 118 and/or the catheter shaft 110; three energy guides 122A can be spaced apart by approximately 120 degrees about the circumference of the guide shaft 118 and/or the catheter shaft 110; four energy guides 122A can be spaced apart by approximately 90 degrees about the circumference of the guide shaft 118 and/or the catheter shaft 110; five energy guides 122A can be spaced apart by approximately 72 degrees about the circumference of the guide shaft 118 and/or the catheter shaft 110; or six energy guides 122A can be spaced apart by approximately 60 degrees about the circumference of the guide shaft 118 and/or the catheter shaft 110. Still alternatively, multiple energy guides 122A need not be uniformly spaced apart from one another about the circumference of the guide shaft 118 and/or the catheter shaft 110. More particularly, it is further appreciated that the energy guides 122A can be disposed uniformly or non-uniformly about the guide shaft 118 and/or the catheter shaft 110 to achieve the desired effect in the desired locations.

The catheter system 100 and/or the energy guide bundle 122 can include any number of energy guides 122A in optical communication with the energy source 124 at the proximal portion 114, and with the balloon fluid 132 within the interstitial space 146A between the balloons 104A, 104B at the distal portion 116. For example, in some embodiments, the catheter system 100 and/or the energy guide bundle 122 can include from one energy guide 122A to greater than 30 energy guides 122A.

The energy guides 122A can have any suitable design for purposes of generating plasma-induced bubbles 134 and/or pressure waves in the balloon fluid 132 within the interstitial space 146A between the balloons 104A, 104B. Thus, the general description of the energy guides 122A as light guides is not intended to be limiting in any manner, except for as set forth in the claims appended hereto. More particularly, although the catheter systems 100 are often described with the energy source 124 as a light source and the one or more energy guides 122A as light guides, the catheter system 100 can alternatively include any suitable energy source 124 and energy guides 122A for purposes of generating the desired plasma-induced bubble(s) 134 in the balloon fluid 132 within the interstitial space 146A between the balloons 104A, 104B. For example, in one non-exclusive alternative embodiment, the energy source 124 can be configured to provide high voltage pulses, and each energy guide 122A can include an electrode pair including spaced apart electrodes that extend into the interstitial space 146A between the balloons 104A, 104B. In such embodiment, each pulse of high voltage is applied to the electrodes and forms an electrical arc across the electrodes, which, in turn, generates the plasma 134 and forms the pressure waves within the balloon fluid 132 that are utilized to provide the fracture force onto the vascular lesions 106A at the treatment site 106. Still alternatively, the energy source 124 and/or the energy guides 122A can have another suitable design and/or configuration.

In certain embodiments, the energy guides 122A can include an optical fiber or flexible light pipe. The energy guides 122A can be thin and flexible and can allow light signals to be sent with very little loss of strength. The energy guides 122A can include a core surrounded by a cladding about its circumference. In some embodiments, the core can be a cylindrical core or a partially cylindrical core. The core and cladding of the energy guides 122A can be formed from one or more materials, including but not limited to one or more types of glass, silica, or one or more polymers. The energy guides 122A may also include a protective coating, such as a polymer. It is appreciated that the index of refraction of the core will be greater than the index of refraction of the cladding.

Each energy guide 122A can guide energy along its length from a guide proximal end 122P to a guide distal end 122D having at least one optical window (not shown) that is positioned within the interstitial space 146A between the balloons 104A, 104B. In one non-exclusive embodiment, the guide distal end 122D of each energy guide 122A can be positioned within the interstitial space 146A so as to be positioned approximately at a midpoint of the heart valve 108. With such design, upon expansion of the balloons 104A, 104B to the inflated state, the pressure waves generated in the balloon fluid 132 within the interstitial space 146A between the balloons 104A, 104B can put pressure on any desired portion of the heart valve 108, e.g., the valve wall 108A, the commissures, the annulus and/or the leaflets 108B. Alternatively, the energy guides 122A can have another suitable design and/or the energy from the energy source 124 can be guided into the interstitial space 146A between the balloons 104A, 104B by another suitable method.

The energy guides 122A can assume many configurations about and/or relative to the catheter shaft 110 of the catheter 102. In some embodiments, the energy guides 122A can run parallel to the longitudinal axis 144 of the catheter shaft 110. In some embodiments, the energy guides 122A can be physically coupled to the catheter shaft 110. In other embodiments, the energy guides 122A can be disposed along a length of an outer diameter of the catheter shaft 110. In yet other embodiments, the energy guides 122A can be disposed within one or more energy guide lumens within the catheter shaft 110.

As noted, in some embodiments, each energy guide 122A can be adhered and/or attached to the outer surface 104S of the inner balloon 104A. With such design, the guide distal end 122D of each energy guide 122A can be positioned substantially directly adjacent to the outer surface 104S of the inner balloon 104A. Alternatively, in other embodiments, one or more of the energy guides 122A can be fixed onto a separate support structure such as a nitinol scaffold. With such alternative design, the guide distal end 122D of each of the energy guides 122A can be positioned spaced apart from the outer surface 104S of the inner balloon 104A.

The energy guides 122A can also be disposed at any suitable positions about the circumference of the guide shaft 118 and/or the catheter shaft 110, and the guide distal end 122D of each of the energy guides 122A can be disposed at any suitable longitudinal position relative to the length of the balloons 104A, 104B and/or relative to the length of the guide shaft 118.

In certain embodiments, the energy guides 122A can include one or more photoacoustic transducers 154, where each photoacoustic transducer 154 can be in optical communication with the energy guide 122A within which it is disposed. In some embodiments, the photoacoustic transducers 154 can be in optical communication with the guide distal end 122D of the energy guide 122A. Additionally, in such embodiments, the photoacoustic transducers 154 can have a shape that corresponds with and/or conforms to the guide distal end 122D of the energy guide 122A.

The photoacoustic transducer 154 is configured to convert light energy into an acoustic wave at or near the guide distal end 122D of the energy guide 122A. The direction of the acoustic wave can be tailored by changing an angle of the guide distal end 122D of the energy guide 122A.

In certain embodiments, the photoacoustic transducers 154 disposed at the guide distal end 122D of the energy guide 122A can assume the same shape as the guide distal end 122D of the energy guide 122A. For example, in certain non-exclusive embodiments, the photoacoustic transducer 154 and/or the guide distal end 122D can have a conical shape, a convex shape, a concave shape, a bulbous shape, a square shape, a stepped shape, a half-circle shape, an ovoid shape, and the like. The energy guide 122A can further include additional photoacoustic transducers 154 disposed along one or more side surfaces of the length of the energy guide 122A.

In some embodiments, the energy guides 122A can further include one or more diverting features or “diverters” (not shown in FIG. 1 ) within the energy guide 122A that are configured to direct energy to exit the energy guide 122A toward a side surface which can be located at or near the guide distal end 122D of the energy guide 122A, and toward the balloon wall 130 of the outer balloon 104B. A diverting feature can include any feature of the system that diverts energy from the energy guide 122A away from its axial path toward a side surface of the energy guide 122A. Additionally, the energy guides 122A can each include one or more optical windows disposed along the longitudinal or circumferential surfaces of each energy guide 122A and in optical communication with a diverting feature. Stated in another manner, the diverting features can be configured to direct energy in the energy guide 122A toward a side surface that is at or near the guide distal end 122D, where the side surface is in optical communication with an optical window. The optical windows can include a portion of the energy guide 122A that allows energy to exit the energy guide 122A from within the energy guide 122A, such as a portion of the energy guide 122A lacking a cladding material on or about the energy guide 122A.

Examples of the diverting features suitable for use include a reflecting element, a refracting element, and a fiber diffuser. The diverting features suitable for focusing energy away from the tip of the energy guides 122A can include, but are not to be limited to, those having a convex surface, a gradient-index (GRIN) lens, and a mirror focus lens. Upon contact with the diverting feature, the energy is diverted within the energy guide 122A to one or more of a plasma generator 133 and the photoacoustic transducer 154 that is in optical communication with a side surface of the energy guide 122A. The photoacoustic transducer 154 then converts light energy into an acoustic wave that extends away from the side surface of the energy guide 122A.

The source manifold 136 can be positioned at or near the proximal portion 114 of the catheter system 100. The source manifold 136 can include one or more proximal end openings that can receive the one or more energy guides 122A of the energy guide bundle 122, the guidewire 112, and/or an inflation conduit 140 that is coupled in fluid communication with the fluid pump 138. The catheter system 100 can also include the fluid pump 138 that is configured to inflate each balloon 104A, 104B of the balloon assembly 104 with the balloon fluid 132, i.e. via the inflation conduit 140, as needed.

As noted above, in the embodiment illustrated in FIG. 1 , the system console 123 includes one or more of the energy source 124, the power source 125, the system controller 126, and the GUI 127. Alternatively, the system console 123 can include more components or fewer components than those specifically illustrated in FIG. 1 . For example, in certain non-exclusive alternative embodiments, the system console 123 can be designed without the GUI 127. Still alternatively, one or more of the energy source 124, the power source 125, the system controller 126, and the GUI 127 can be provided within the catheter system 100 without the specific need for the system console 123.

As shown, the system console 123, and the components included therewith, is operatively coupled to the catheter 102, the energy guide bundle 122, and the remainder of the catheter system 100. For example, in some embodiments, as illustrated in FIG. 1 , the system console 123 can include a console connection aperture 148 (also sometimes referred to generally as a “socket”) by which the energy guide bundle 122 is mechanically coupled to the system console 123. In such embodiments, the energy guide bundle 122 can include a guide coupling housing 150 (also sometimes referred to generally as a “ferrule”) that houses a portion, e.g., the guide proximal end 122P, of each of the energy guides 122A. The guide coupling housing 150 is configured to fit and be selectively retained within the console connection aperture 148 to provide the mechanical coupling between the energy guide bundle 122 and the system console 123.

The energy guide bundle 122 can also include a guide bundler 152 (or “shell”) that brings each of the individual energy guides 122A closer together so that the energy guides 122A and/or the energy guide bundle 122 can be in a more compact form as it extends with the catheter 102 into the heart valve 108 during use of the catheter system 100.

The energy source 124 can be selectively and/or alternatively coupled in optical communication with each of the energy guides 122A, i.e. to the guide proximal end 122P of each of the energy guides 122A, in the energy guide bundle 122. In particular, the energy source 124 is configured to generate energy in the form of a source beam 124A, such as a pulsed source beam, that can be selectively and/or alternatively directed to and received by each of the energy guides 122A in the energy guide bundle 122 as an individual guide beam 124B. Alternatively, the catheter system 100 can include more than one energy source 124. For example, in one non-exclusive alternative embodiment, the catheter system 100 can include a separate energy source 124 for each of the energy guides 122A in the energy guide bundle 122.

The energy source 124 can have any suitable design. In certain embodiments, the energy source 124 can be configured to provide sub-millisecond pulses of energy from the energy source 124 that are focused onto a small spot in order to couple it into the guide proximal end 122P of the energy guide 122A. Such pulses of energy are then directed and/or guided along the energy guides 122A to a location within the interstitial space 146A between the balloons 104A, 104B, thereby inducing the formation of plasma-induced bubble(s) (134) in the balloon fluid 132 within the interstitial space 146A between the balloons 104A, 104B, e.g., via the plasma generator 133 that can be located at or near the guide distal end 122D of the energy guide 122A. In particular, the energy emitted at the guide distal end 122D of the energy guide 122A energizes the plasma generator 133 to form the plasma-induced bubble 134 in the balloon fluid 132 within the interstitial space 146A between the balloons 104A, 104B. Formation of the plasma-induced bubble(s) 134 imparts pressure waves upon the treatment site 106. One exemplary plasma-induced bubble 134 is illustrated in FIG. 1 .

In various non-exclusive alternative embodiments, the sub-millisecond pulses of energy from the energy source 124 can be delivered to the treatment site 106 at a frequency of between approximately one hertz (Hz) and 5000 Hz, between approximately 30 Hz and 1000 Hz, between approximately ten Hz and 100 Hz, or between approximately one Hz and 30 Hz. Alternatively, the sub-millisecond pulses of energy can be delivered to the treatment site 106 at a frequency that can be greater than 5000 Hz or less than one Hz, or any other suitable range of frequencies.

It is appreciated that although the energy source 124 is typically utilized to provide pulses of energy, the energy source 124 can still be described as providing a single source beam 124A, i.e. a single pulsed source beam.

The energy sources 124 suitable for use can include various types of light sources including lasers and lamps. Alternatively, the energy sources 124 can include any suitable type of energy source.

Suitable lasers can include short pulse lasers on the sub-millisecond timescale. In some embodiments, the energy source 124 can include lasers on the nanosecond (ns) timescale. The lasers can also include short pulse lasers on the picosecond (ps), femtosecond (fs), and microsecond (us) timescales. It is appreciated that there are many combinations of laser wavelengths, pulse widths and energy levels that can be employed to generate plasma-induced bubble(s) 134 in the balloon fluid 132 of the catheter 102. In various non-exclusive alternative embodiments, the pulse widths can include those falling within a range including from at least ten ns to 3000 ns, at least 20 ns to 100 ns, or at least one ns to 500 ns. Alternatively, any other suitable pulse width range can be used.

Exemplary nanosecond lasers can include those within the UV to IR spectrum, spanning wavelengths of about ten nanometers (nm) to one millimeter (mm). In some embodiments, the energy sources 124 suitable for use in the catheter systems 100 can include those capable of producing light at wavelengths of from at least 750 nm to 2000 nm. In other embodiments, the energy sources 124 can include those capable of producing light at wavelengths of from at least 700 nm to 3000 nm. In still other embodiments, the energy sources 124 can include those capable of producing light at wavelengths of from at least 100 nm to ten micrometers (μm). Nanosecond lasers can include those having repetition rates of up to 200 kHz.

In some embodiments, the laser can include a Q-switched thulium:yttrium-aluminum-garnet (Tm:YAG) laser. In other embodiments, the laser can include a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, holmium:yttrium-aluminum-garnet (Ho:YAG) laser, erbium:yttrium-aluminum-garnet (Er:YAG) laser, excimer laser, helium-neon laser, carbon dioxide laser, as well as doped, pulsed, fiber lasers.

The catheter system 100 can generate pressure waves having maximum pressures in the range of at least one megapascal (MPa) to 100 MPa. The maximum pressure generated by a particular catheter system 100 will depend on the energy source 124, the absorbing material, the bubble expansion, the propagation medium, the balloon material, and other factors. In various non-exclusive alternative embodiments, the catheter systems 100 can generate pressure waves having maximum pressures in the range of at least approximately two MPa to 50 MPa, at least approximately two MPa to 30 MPa, or at least approximately 15 MPa to 25 MPa.

The pressure waves can be imparted upon the treatment site 106 from a distance within a range from at least approximately 0.1 millimeters (mm) to greater than approximately 25 mm extending radially from the energy guides 122A when the catheter 102 is placed at the treatment site 106. In various non-exclusive alternative embodiments, the pressure waves can be imparted upon the treatment site 106 from a distance within a range from at least approximately ten mm to 20 mm, at least approximately one mm to ten mm, at least approximately 1.5 mm to four mm, or at least approximately 0.1 mm to ten mm extending radially from the energy guides 122A when the catheter 102 is placed at the treatment site 106. In other embodiments, the pressure waves can be imparted upon the treatment site 106 from another suitable distance that is different than the foregoing ranges. In some embodiments, the pressure waves can be imparted upon the treatment site 106 within a range of at least approximately two MPa to 30 MPa at a distance from at least approximately 0.1 mm to ten mm. In some embodiments, the pressure waves can be imparted upon the treatment site 106 from a range of at least approximately two MPa to 25 MPa at a distance from at least approximately 0.1 mm to ten mm. Still alternatively, other suitable pressure ranges and distances can be used.

The power source 125 is electrically coupled to and is configured to provide necessary power to each of the energy source 124, the system controller 126, the GUI 127, and the handle assembly 128. The power source 125 can have any suitable design for such purposes.

The system controller 126 is electrically coupled to and receives power from the power source 125. Additionally, the system controller 126 is coupled to and is configured to control operation of each of the energy source 124 and the GUI 127. The system controller 126 can include one or more processors or circuits for purposes of controlling the operation of at least the energy source 124 and the GUI 127. For example, the system controller 126 can control the energy source 124 for generating pulses of energy as desired and/or at any desired firing rate. Additionally, the system controller 126 can operate to effectively and efficiently provide the desired fracture forces adjacent to and/or on or between adjacent leaflets 108B within the heart valve 108 at the treatment site 106.

The system controller 126 can also be configured to control operation of other components of the catheter system 100 such as the positioning of the catheter 102 and/or the balloon assembly 104 adjacent to the treatment site 106, the inflation of each balloon 104A, 104B with the balloon fluid 132, etc. Further, or in the alternative, the catheter system 100 can include one or more additional controllers that can be positioned in any suitable manner for purposes of controlling the various operations of the catheter system 100. For example, in certain embodiments, an additional controller and/or a portion of the system controller 126 can be positioned and/or incorporated within the handle assembly 128.

The GUI 127 is accessible by the user or operator of the catheter system 100. Additionally, the GUI 127 is electrically connected to the system controller 126. With such design, the GUI 127 can be used by the user or operator to ensure that the catheter system 100 is effectively utilized to impart pressure onto and induce fractures into the vascular lesions 106A at the treatment site 106. The GUI 127 can provide the user or operator with information that can be used before, during and after use of the catheter system 100. In one embodiment, the GUI 127 can provide static visual data and/or information to the user or operator. In addition, or in the alternative, the GUI 127 can provide dynamic visual data and/or information to the user or operator, such as video data or any other data that changes over time during use of the catheter system 100. In various embodiments, the GUI 127 can include one or more colors, different sizes, varying brightness, etc., that may act as alerts to the user or operator. Additionally, or in the alternative, the GUI 127 can provide audio data or information to the user or operator. The specifics of the GUI 127 can vary depending upon the design requirements of the catheter system 100, or the specific needs, specifications and/or desires of the user or operator.

As shown in FIG. 1 , the handle assembly 128 can be positioned at or near the proximal portion 114 of the catheter system 100, and/or near the source manifold 136. In this embodiment, the handle assembly 128 is coupled to the balloon assembly 104 and is positioned spaced apart from the balloon assembly 104. Alternatively, the handle assembly 128 can be positioned at another suitable location.

The handle assembly 128 is handled and used by the user or operator to operate, position and control the catheter 102. The design and specific features of the handle assembly 128 can vary to suit the design requirements of the catheter system 100. In the embodiment illustrated in FIG. 1 , the handle assembly 128 is separate from, but in electrical and/or fluid communication with one or more of the system controller 126, the energy source 124, the fluid pump 138, and the GUI 127. In some embodiments, the handle assembly 128 can integrate and/or include at least a portion of the system controller 126 within an interior of the handle assembly 128. For example, as shown, in certain such embodiments, the handle assembly 128 can include circuitry 156 that can form at least a portion of the system controller 126. In one embodiment, the circuitry 156 can include a printed circuit board having one or more integrated circuits, or any other suitable circuitry. In an alternative embodiment, the circuitry 156 can be omitted, or can be included within the system controller 126, which in various embodiments can be positioned outside of the handle assembly 128, e.g., within the system console 123. It is understood that the handle assembly 128 can include fewer or additional components than those specifically illustrated and described herein.

Descriptions of various embodiments and implementations of the balloon assembly 104, and usages thereof, are described in detail herein below. However, it is further appreciated that alternative embodiments and implementations may also be employed that would be apparent to those skilled in the relevant art based on the teachings provided herein. Thus, the scope of the present embodiments and implementations is not intended to be limited to just those specifically described herein, except as recited in the claims appended hereto.

FIG. 2A is a simplified side view of a portion of the heart valve 108, including the valve wall 108A and the leaflets 108B, and a portion of an embodiment of the catheter system 200 including an embodiment of the valvular lithoplasty balloon assembly 204. The balloon assembly 204 is again configured to be selectively positioned adjacent to the valve wall 108A and/or between adjacent leaflets 108B within the heart valve 108 at a treatment site 106 including vascular lesions 106A within the body 107 and the patient 109.

Similar to the previous embodiments, the catheter system 200 includes a catheter 202 including a catheter shaft 210, a guide shaft 218, and a guidewire 212, such as described above, and the balloon assembly 204. Additionally, the catheter system 200 will typically include various other components such as illustrated and described in relation to FIG. 1 . However, such additional components are not shown in FIG. 2A for purposes of clarity.

As shown in the embodiment illustrated in FIG. 2A, the balloon assembly 204 includes an inner balloon 204A and an outer balloon 204B, which is positioned to substantially, if not entirely, encircle the inner balloon 204A. Stated in another manner, the balloon assembly 204 includes the outer balloon 204B, and the inner balloon 204A that is positioned at least substantially, if not entirely, within the outer balloon 204B. During use of the catheter system 200, the outer balloon 204B can be positioned adjacent to the valve wall 108A and/or on or between adjacent leaflets 108B within the heart valve 108 at the treatment site 106.

Each balloon 204A, 204B can include a balloon proximal end 204P and a balloon distal end 204D. As illustrated, in certain implementations, the balloon proximal end 204P of at least one of the balloons 204A, 204B can be coupled to the catheter shaft 210, and the balloon distal end 204D of at least one of the balloons 204A, 204B can be coupled to the guide shaft 218. For example, in some such implementations, the balloon proximal end 204P of the inner balloon 204A is coupled to and/or secured to the catheter shaft 210 and the balloon distal end 204D of the inner balloon 204A is coupled to and/or secured to the guide shaft 218. In such implementations, the balloon proximal end 204P of the outer balloon 204B can also be coupled to and/or secured to the catheter shaft 210, and/or the balloon proximal end 204P of the outer balloon 204B can be coupled to and/or secured to the balloon proximal end 204P of the inner balloon 204A. Additionally, in such implementations, the balloon distal end 204D of the outer balloon 204B can also be coupled to and/or secured to the guide shaft 218, and/or the balloon distal end 204D of the outer balloon 204A can be coupled to and/or secured to the balloon distal end 204D of the inner balloon 204A.

FIG. 2A further illustrates that the catheter system 200 includes one or more energy guides 222A (three are visible in FIG. 2A) that extend into the interstitial space 246A between the inner balloon 204A and the outer balloon 204B that is created when the balloons 204A, 204B are in the inflated state (as shown in FIG. 2A).

FIG. 2B is a simplified cutaway view of the heart valve 108 and the valvular lithoplasty balloon assembly 204 taken on line 2B-2B in FIG. 2A. It is appreciated that the Figures herein, including FIG. 2B, are not necessarily drawn to scale, but rather are drawn to more clearly illustrate the relative positioning of the components of the catheter system 200.

As shown, the balloon assembly 204 can be positioned within the heart valve 108, and with the outer balloon 204B of the balloon assembly 204 being positioned adjacent to the valve wall 108A and/or between adjacent leaflets 108B (illustrated in FIG. 2A) within the heart valve 108. The balloon assembly 204 is also illustrated as being positioned about the guide shaft 218, which provides the conduit through which the guidewire 212 extends, in this non-exclusive implementation.

Additionally, each balloon 204A, 204B can include a balloon wall 230 that defines a balloon interior 246, and that is configured to receive the balloon fluid 232 (illustrated in FIG. 2A) within the balloon interior 246 of each balloon 204A, 204B and/or within the interstitial space 246A between the balloons 204A, 204B. Each balloon 204A, 204B can thus be selectively inflated with the balloon fluid 232 to expand from the deflated state to the inflated state (as shown in FIG. 2B).

Also illustrated in FIG. 2B are the one or more energy guides 222A. A portion of each energy guide 222A, i.e. the guide distal end 222D, can be positioned in the balloon fluid 232 within the balloon interior 246 of the outer balloon 204B and/or within the interstitial space 246A between the balloons 204A, 204B. In this embodiment, the catheter system 200 includes four energy guides 222A, with the guide distal end 222D of each of the four energy guides 222A positioned in the balloon fluid 232 within the balloon interior 246 of the outer balloon 204B and/or within the interstitial space 246A between the balloons 204A, 204B. In one non-exclusive embodiment, the guide distal end 222D of the four energy guides 222A can be substantially uniformly spaced apart from one another by approximately 90 degrees about the inner balloon 204A. Alternatively, the catheter system 200 can include greater than four energy guides 222A or fewer than four energy guides 222A provided that the guide distal end 222D of at least one energy guide 222A is positioned within the balloon interior 246 of the outer balloon 204B and/or within the interstitial space 246A between the balloons 204A, 204B.

In this embodiment, the interstitial space 246A between the balloons 204A, 204B is created, at least in part, by a diameter of each balloon 204A, 204B being different from one another when the balloons 204A, 204B are in the inflated state. More specifically, the inner balloon 204A includes an inner balloon diameter 204AD when the inner balloon 204A is in the inflated state, and the outer balloon 204B includes an outer balloon diameter 204BD when the outer balloon 204B is in the inflated state, with the outer balloon diameter 204BD being different than, i.e. greater than, the inner balloon diameter 204AD. In certain non-exclusive alternative embodiments, the outer balloon diameter 204BD when in the inflated state can be at least approximately 1%, 2%, 3%, 5%, 7%, 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47% or 50% greater than the inner balloon diameter 204AD when the inner balloon 204A is also in the inflated state. Alternatively, the difference between the outer balloon diameter 204BD of the outer balloon 204B and the inner balloon diameter 204AD of the inner balloon 204A can be different than the values noted above.

It is appreciated that in this embodiment, the balloons 204A, 204B can also have different shapes from one another and/or be formed from different materials from one another, e.g., with different compliances and/or different expansion rates, to further assist in the creation of the interstitial space 246A between the balloons 204A, 204B.

The energy guides 222A are configured to guide energy from the energy source 124 (illustrated in FIG. 1 ) to induce formation of plasma-induced bubble(s) 134 (illustrated in FIG. 1 ) in the balloon fluid 232 within the balloon interior 246 of the outer balloon 204B and/or within the interstitial space 246A between the balloons 204A, 204B, e.g., via a plasma generator 133 (illustrated in FIG. 1 ) located at or near the guide distal end 222D of the respective energy guide 222A. The formation of plasma-induced bubble(s) 134 imparts pressure waves and/or fracture forces upon the treatment site 106 (illustrated in FIG. 2A). Such pressure waves and/or fracture forces are utilized to break apart the vascular lesions 106A (illustrated in FIG. 2A) at specific precise locations within the heart valve 108 at the treatment site 106. More particularly, by selectively positioning the balloon assembly 204 adjacent to the treatment site 106, each of the energy guides 222A can be applied to break up the calcified vascular lesions 106A in a different precise location at the treatment site 106.

It is further appreciated that in some embodiments, the inner balloon 204A and the outer balloon 204B can be inflated to different inflation pressures, i.e. with the inner balloon 204A pressurized at a higher inflation pressure than the outer balloon 204B to improve the energy transfer by better directing the energy into the vascular lesions 106A at the treatment site 106. More specifically, the improved energy transfer is achieved by keeping the balloon wall 230 of the inner balloon 204A immovable at high pressure so that the energy is not absorbed by movement of the balloon wall 230 of the inner balloon 204A, but rather is directed in a generally outward direction to the balloon wall 230 of the outer balloon 204B positioned at the treatment site 106.

It is appreciated that bubble energy transfer from the energy guide 222A and/or the plasma generator 133 to the calcified vascular lesion 106A at the treatment site 106 is further enhanced as the balloon assembly 204 is expanded by keeping the position of the energy guides 222A and/or the plasma generators 133 close to the treatment site 106 as the diameter of the heart valve 108 expands during valvuloplasty treatment.

As shown in this embodiment, the energy guides 222A can be coupled to and/or secured to an outer surface 204S of the inner balloon 204A, e.g., with the guide distal end 222D of the energy guide 222A positioned substantially directly adjacent to the outer surface 204S of the inner balloon 204A. The energy guides 222A can be coupled to and/or secured to the outer surface 204S of the inner balloon 204A in any suitable manner. For example, in one non-exclusive embodiment, the energy guides 222A can be secured to the outer surface 204S of the inner balloon 204A with an adhesive material. Alternatively, the energy guides 222A can be coupled to and/or secured to the outer surface 204S of the inner balloon 204A in another suitable manner. Still alternatively, in other embodiments, the energy guides 222A can be positioned such that the guide distal end 222D of the energy guide 222A is positioned spaced apart from the outer surface 204S of the inner balloon 204A.

FIG. 3 is a simplified cutaway view of a portion of the heart valve 108, and a portion of another embodiment of the catheter system 300 including another embodiment of the valvular lithoplasty balloon assembly 304. The balloon assembly 304 is again configured to be selectively positioned adjacent to the valve wall 108A and/or between adjacent leaflets 108B (illustrated in FIG. 1 ) within the heart valve 108.

The balloon assembly 304 is substantially similar to what has been illustrated and described in relation to the previous embodiments. For example, in this embodiment, the balloon assembly 304 again includes an inner balloon 304A and an outer balloon 304B, which is positioned to substantially, if not entirely, encircle the inner balloon 304A. Stated in another manner, the balloon assembly 304 includes the outer balloon 304B, and the inner balloon 304A that is positioned at least substantially, if not entirely, within the outer balloon 304B. During use of the catheter system 300, the outer balloon 304B can again be positioned adjacent to the valve wall 108A and/or on or between adjacent leaflets 108B within the heart valve 108 at the treatment site 106 (illustrated in FIG. 1 ). The balloon assembly 304 is also illustrated as being positioned about the guide shaft 318, which provides the conduit through which the guidewire 312 extends, in this non-exclusive implementation.

Additionally, the balloons 304A, 304B of the balloon assembly 304 can again be coupled to and/or secured to the catheter shaft 110 (illustrated in FIG. 1 ) and the guide shaft 318 and/or to one another in a manner substantially similar to what has been described herein above.

Each balloon 304A, 304B can again include a balloon wall 330 that defines a balloon interior 346, and that is configured to receive the balloon fluid 132 (illustrated in FIG. 1 ) within the balloon interior 346 of each balloon 304A, 304B and/or within the interstitial space 346A between the balloons 304A, 304B. Each balloon 304A, 304B can thus be selectively inflated with the balloon fluid 132 to expand from the deflated state to the inflated state (as shown in FIG. 3 ).

In this embodiment, the interstitial space 346A can again be created between the balloons 304A, 304B by one or more of having the balloons 304A, 304B have different diameters than one another when in the inflated state; having the balloons 304A, 304B be of different shapes from one another when in the inflated state; and having the balloons 304A, 304B be formed from different materials from one another so that they have different compliance and/or different expansion rates as the balloons 304A, 304B are moved to the inflated state.

FIG. 3 also illustrates the one or more energy guides 322A (four energy guides 322A are shown in FIG. 3 ) that can be positioned at least in part within the balloon interior 346 of the outer balloon 304B and/or within the interstitial space 346A between the balloons 304A, 304B. More particularly, as shown, the guide distal end 322D of each of the energy guides 322A is shown as being positioned within the balloon interior 346 of the outer balloon 304B and/or within the interstitial space 346A between the balloons 304A, 304B. Although four energy guides 322A are specifically illustrated in FIG. 3 , it is appreciated that the catheter system 300 can include any suitable number of energy guides 322A, which can also be greater than four or less than four energy guides 322A. Additionally, the energy guides 322A can have any desired spacing relative to one another about the inner balloon 304A.

Similar to the previous embodiments, the energy guides 322A are again configured to guide energy from the energy source 124 (illustrated in FIG. 1 ) to induce formation of plasma-induced bubble(s) 134 (illustrated in FIG. 1 ) in the balloon fluid 132 within the balloon interior 346 of the outer balloon 304B and/or within the interstitial space 346A between the balloons 304A, 304B, e.g., via a plasma generator 133 (illustrated in FIG. 1 ) located at or near the guide distal end 322D of the respective energy guide 322A. The formation of plasma-induced bubble(s) 134 imparts pressure waves and/or fracture forces upon the treatment site 106. Such pressure waves and/or fracture forces are utilized to break apart the vascular lesions 106A (illustrated in FIG. 1 ) at specific precise locations within the heart valve 108 at the treatment site 106. More particularly, by selectively positioning the balloon assembly 304 adjacent to the treatment site 106, each of the energy guides 322A can be applied to break up the calcified vascular lesions 106A in a different precise location at the treatment site 106.

It is further appreciated that in some embodiments, the inner balloon 304A and the outer balloon 304B can be inflated to different inflation pressures, i.e. with the inner balloon 304A pressurized at a higher inflation pressure than the outer balloon 304B to improve the energy transfer by better directing the energy into the vascular lesions 106A at the treatment site 106. More specifically, the improved energy transfer is achieved by keeping the balloon wall 330 of the inner balloon 304A immovable at high pressure so that the energy is not absorbed by movement of the balloon wall 330 of the inner balloon 304A, but rather is directed in a generally outward direction to the balloon wall 330 of the outer balloon 304B positioned at the treatment site 106. Bubble energy transfer from the energy guide 322A and/or the plasma generator 133 to the calcified vascular lesion 106A at the treatment site 106 is further enhanced as the balloon assembly 304 is expanded by keeping the position of the energy guides 322A and/or the plasma generators 133 close to the treatment site 106 as the diameter of the heart valve 108 expands during valvuloplasty treatment.

As shown in this embodiment, the energy guides 322A can be positioned spaced apart from an outer surface 304S of the inner balloon 304A, e.g., with the guide distal end 322D of the energy guide 322A positioned spaced apart from the outer surface 304S of the inner balloon 304A. The energy guides 3222A can be positioned spaced apart from the outer surface 304S of the inner balloon 304A in any suitable manner. For example, in some non-exclusive embodiments, the energy guides 322A can be secured to and/or positioned on a guide support structure 360 that is mounted on the outer surface 304S of the inner balloon 304A. In one such embodiment, the guide support structure 360 can be provided in the form of a nitinol scaffold that supports the guide distal end 322D of the respective energy guide 322A spaced apart from the outer surface 304S of the inner balloon 304A. Alternatively, the guide support structure 360 can have a different design and/or the energy guides 322A can be maintained spaced apart from the outer surface 304S of the inner balloon 304A in a different manner.

FIG. 4 is a simplified side view of a portion of a fluid flow system 470 usable within the catheter system 400. In particular, the fluid flow system 470 is configured to provide and/or direct the balloon fluid 132 (illustrated in FIG. 1 ) into each of the inner balloon 404A and the outer balloon 404B of the balloon assembly 404. FIG. 4 also illustrates the catheter shaft 410, the guide shaft 418 and the guidewire 412 of the catheter system 400.

The design of the fluid flow system 470 can be varied to suit the specific requirements of the catheter system 400. In certain embodiments, the fluid flow system 470 can include a first flow system 472A that is configured to provide and/or direct the balloon fluid 132 into the inner balloon 404A, and a second flow system 472B that is configured to provide and/or direct the balloon fluid 132 into the outer balloon 404B.

The design of each of the first flow system 472A and the second flow system 472B can be substantially similar to one another. More specifically, in the embodiment illustrated in FIG. 4 , the first flow system 472A includes a first fluid pump 474A, a first inflation conduit 476A, and a first seal assembly 478A, and the second flow system 472B includes a second fluid pump 474B, a second inflation conduit 476B, and a second seal assembly 478B. Alternatively, the first flow system 472A and/or the second flow system 472B can include more components or fewer components than those specifically illustrated and described in relation to FIG. 4 .

As shown, the first fluid pump 474A is configured to pump the balloon fluid 132 through the first fluid conduit 476A and into the balloon interior 146 (illustrated in FIG. 1 ) of the inner balloon 404A. The first seal assembly 478A can seal the connection of the first fluid conduit 476A into the balloon interior 146 of the inner balloon 404A. The first seal assembly 478A can have any suitable design for purposes of sealing the connection of the first fluid conduit 476A into the balloon interior 146 of the inner balloon 404A.

Similarly, the second fluid pump 474B is configured to pump the balloon fluid 132 through the second fluid conduit 476B and into the balloon interior 146 (illustrated in FIG. 1 ) of the outer balloon 404B. The second seal assembly 478B can seal the connection of the second fluid conduit 476B into the balloon interior 146 of the outer balloon 404B. The second seal assembly 478B can have any suitable design for purposes of sealing the connection of the second fluid conduit 476B into the balloon interior 146 of the outer balloon 404B.

In alternative embodiments, the fluid flow system 470 can be configured to include a single fluid pump that is utilized to pump the balloon fluid 132 through each of the first fluid conduit 476A and into the balloon interior 146 of the inner balloon 404A, and the second fluid conduit 476B and into the balloon interior 146 of the outer balloon 404B. More particularly, in such alternative embodiments, the single fluid pump can be provided with two pressure-regulated flow valves for each balloon 404A, 404B.

It should be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content and/or context clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content or context clearly dictates otherwise.

It should also be noted that, as used in this specification and the appended claims, the phrase “configured” describes a system, apparatus, or other structure that is constructed or configured to perform a particular task or adopt a particular configuration. The phrase “configured” can be used interchangeably with other similar phrases such as arranged and configured, constructed and arranged, constructed, manufactured and arranged, and the like.

The headings used herein are provided for consistency with suggestions under 37 CFR 1.77 or otherwise to provide organizational cues. These headings shall not be viewed to limit or characterize the invention(s) set out in any claims that may issue from this disclosure. As an example, a description of a technology in the “Background” is not an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” or “Abstract” to be considered as a characterization of the invention(s) set forth in issued claims.

The embodiments described herein are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices. As such, aspects have been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope herein.

It is understood that although a number of different embodiments of the catheter systems have been illustrated and described herein, one or more features of any one embodiment can be combined with one or more features of one or more of the other embodiments, provided that such combination satisfies the intent of the present invention.

While a number of exemplary aspects and embodiments of the catheter systems have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope, and no limitations are intended to the details of construction or design herein shown. 

What is claimed is:
 1. A catheter system for treating a treatment site within or adjacent to a heart valve within a body of a patient, the catheter system comprising: an energy source that generates energy; an energy guide that is configured to receive energy from the energy source; and a balloon assembly that is positionable adjacent to the treatment site, the balloon assembly including an outer balloon and an inner balloon that is positioned substantially within the outer balloon, each of the balloons having a balloon wall that defines a balloon interior, each of the balloons being configured to retain a balloon fluid within the balloon interior, the balloon wall of the inner balloon being positioned spaced apart from the balloon wall of the outer balloon to define an interstitial space therebetween; wherein a portion of the energy guide is positioned within the interstitial space between the balloons to generate plasma-induced bubble formation in the balloon fluid within the interstitial space upon the energy guide receiving energy from the energy source.
 2. The catheter system of claim 1 wherein the energy guide includes a guide distal end that is positioned within the interstitial space between the balloons so that a plasma-induced bubble is formed in the balloon fluid within the interstitial space.
 3. The catheter system of claim 1 wherein each of the balloons is selectively inflatable with the balloon fluid to expand to an inflated state, and wherein when the balloons are in the inflated state the balloon wall of the inner balloon is spaced apart from the balloon wall of the outer balloon to define the interstitial space therebetween.
 4. The catheter system of claim 3 wherein when the balloons are in the inflated state, the outer balloon is configured to be positioned substantially adjacent to the treatment site.
 5. The catheter system of claim 3 wherein when the balloons are in the inflated state, the inner balloon has an inner balloon diameter, and the outer balloon has an outer balloon diameter that is greater than the inner balloon diameter of the inner balloon.
 6. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 5% greater than the inner balloon diameter of the inner balloon.
 7. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 10% greater than the inner balloon diameter of the inner balloon.
 8. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 20% greater than the inner balloon diameter of the inner balloon.
 9. The catheter system of claim 5 wherein when the balloons are in the inflated state, the outer balloon diameter of the outer balloon is at least approximately 30% greater than the inner balloon diameter of the inner balloon.
 10. The catheter system of claim 3 wherein when the balloons are in the inflated state, the inner balloon is inflated to a greater inflation pressure than the outer balloon.
 11. The catheter system of claim 3 wherein when the balloons are in the inflated state, the inner balloon has a first balloon shape and the outer balloon has a second balloon shape that is different from the first balloon shape.
 12. The catheter system of claim 1 wherein the inner balloon is made from a first material, and wherein the outer balloon is made from a second material that is different from the first material.
 13. The catheter system of claim 12 wherein the first material has a first compliance, and wherein the second material has a second compliance that is greater than the first compliance so that the outer balloon expands at a faster rate than the inner balloon when the balloons are expanded to an inflated state.
 14. The catheter system of claim 12 wherein the first material is non-compliant, and wherein the second material is semi-compliant.
 15. The catheter system of claim 12 wherein the first material is non-compliant, and wherein the second material is compliant.
 16. The catheter system of claim 12 wherein the first material is semi-compliant, and wherein the second material is compliant.
 17. The catheter system of claim 1 wherein the energy guide is positioned substantially directly adjacent to an outer surface of the inner balloon.
 18. The catheter system of claim 17 wherein the energy guide is adhered to the outer surface of the inner balloon.
 19. The catheter system of claim 1 wherein the energy guide is positioned spaced apart from the outer surface of the inner balloon.
 20. The catheter system of claim 19 further comprising a guide support structure that is mounted on the outer surface of the inner balloon, and wherein the energy guide is positioned on the guide support structure so that the energy guide is positioned spaced apart from the outer surface of the inner balloon.
 21. The catheter system of claim 1 wherein the heart valve includes a valve wall; and wherein the balloon assembly is positioned adjacent to the valve wall.
 22. The catheter system of claim 1 wherein the heart valve includes a plurality of leaflets; and wherein the balloon assembly is positioned adjacent to at least one of the plurality of leaflets.
 23. The catheter system of claim 1 further comprising a plasma generator that is positioned near a guide distal end of the energy guide, the plasma generator being configured to generate the plasma-induced bubble in the balloon fluid within the interstitial space between the balloons.
 24. The catheter system of claim 23 wherein the guide distal end of the energy guide is positioned within the interstitial space between the balloons approximately at a midpoint of the heart valve.
 25. The catheter system of claim 1 wherein the formation of the plasma-induced bubble imparts pressure waves upon the balloon wall of the outer balloon adjacent to the treatment site.
 26. The catheter system of claim 1 wherein the energy source generates pulses of energy that are guided along the energy guide into the interstitial space between the balloons to induce the plasma-induced bubble formation in the balloon fluid within the interstitial space between the balloons.
 27. The catheter system of claim 1 wherein the energy source is a laser source that provides pulses of laser energy.
 28. The catheter system of claim 1 wherein the energy guide includes an optical fiber.
 29. The catheter system of claim 1 wherein the energy source is a high voltage energy source that provides pulses of high voltage.
 30. The catheter system of claim 1 wherein the energy guide includes an electrode pair including spaced apart electrodes that extend into the interstitial space between the balloons; and wherein pulses of high voltage from the energy source are applied to the electrodes and form an electrical arc across the electrodes. 